Variation in grafted European chestnut and hybrids by microsatellites reveals two main origins in the Iberian Peninsula

Abstract

This is the first known large-scale molecular study of simple sequence repeats (SSR) loci based on samples from grafted trees found in the Iberian Peninsula and Canary Islands and hybrids. Interspecific hybrids resistant to 'ink disease' (Phytophthora spp.) were obtained in France, Portugal and Spain, although difficult to distinguish by morphology. This study focuses on genetic variation using 10 SSRs (11 unlinked loci) from clonally propagated cultivars (574 accessions) of European chestnut (Castanea sativa) and hybrids (71 accessions). They were compared with a representative sample of exotic chestnut species present in the Atlantic area, 47 accessions of Castanea crenata, 37 of Castanea mollissima and 33 of Castanea henryi. Accessions were analysed using a modelbased Bayesian procedure (Structure), factorial correspondence analysis and analysis of molecular variance. The main chestnut species, hybrids and alien introgressions were differentiated. Two main origins of variability in European cultivated chestnut were found in the Iberian Peninsula, one in the North and a second in the Centre. Andalusian and Canary Island accessions could be assigned to both of these zones, which indicate that they could have been colonised with cultivars originating from either zone, in the case of the Canary Islands from the sixteenth century on.

Genetic characterization of chestnut (Castanea sativa Mill.) orchards and traditional nut varieties in El Bierzo, a glacial refuge and major cultivation site in northwestern Spain

“…1). Recent studies have analyzed grafted trees from this region, hinting at their relationships with other major production areas (Pereira-Lorenzo et al 2010aMartin et al 2012). However, these works had a much broader geographical scope and did not include sufficient local samples for a detailed genetic characterization.…”

“…It is well established that both factors influence the genetic makeup of crops, especially when clonal effects take place (Jarvis et al 2008;Pusadee et al 2009;Myles et al 2011). In the case of chestnut, domestication history has already been shown to affect genetic structure (Forneck 2005;Mattioni et al 2008;Pereira-Lorenzo et al 2010a). It is noteworthy that most genotypes representing traditional nut varieties in El Bierzo could be readily assigned to one of the three aforementioned clusters (data not shown; discussed below).…”

“…The northwest region of the Iberian Peninsula is particularly interesting in this context because (i) it is located at one extreme of the distribution area and concentrates the most extensive sweet chestnut stands in Spain and Portugal, (ii) it has been one of the major focal points for the native species after the last glaciation, and (iii) it has a centenary tradition of chestnut cultivation and management Ramos-Cabrer and PereiraLorenzo 2005;Pereira-Lorenzo et al 2010aMartin et al 2012;Mattioni et al 2013). This region hosts nowadays prime orchards for commercial nut production, located mainly in Galicia and El Bierzo (Castile and Leon) (Rubio 2009).…”

“…To date, some local C. sativa samples have been analyzed in El Bierzo using molecular markers, but only as part of broad studies aimed at establishing large-scale genetic structure and relationships (Pereira-Lorenzo et al 2010aMartin et al 2012). Germplasm and nuts are thus poorly characterized in this region, which awaits more focused analyses with sufficiently large samples.…”

Study of morphological and chemical diversity in chestnut trees (var. “Judia”) as a function of temperature sum Estudio de la diversidad morfológica y química del fruto de castaña (var. “Judia”) en función de la suma de la temperatura

“…We studied nine polymorphic and unliked SSR: CsCAT 3, CsCAT 16, CsCAT 14, and CsCAT 41 (Marinoni, Akkak, Bounous, Edwards, & Botta, 2003), EMCs 2, EmCs 14, and EMCs 15 (Buck, Hadonou, James, Blakesley, & Russel, 2003) developed for Castanea sativa and QpZAG 36 and QpZAG 110 (Kampfer, Lexer, Glo¨ssl, & Steinkellner, 1998;Steinkellner et al, 1997) developed for Quercus petrae. DNA extraction and amplification of microsatellite loci were done following the same methodology used by Pereira-Lorenzo et al (2010).…”